libwmf-0.2.0 Tutorial 2: The IPA

Contents

• Introduction
• Types
• IPA Function Reference
• IPA Functions
• Bitmap Functions
• Other Functions
• Guidelines
• Compiling - The Distribution

This is a combination of tutorial and reference guide for writing new device layers for libwmf.

Since no two graphics interfaces are identical, the task of the IPA (the interface between the interpreter and the device layer) is to simplify the task of translating the metafile drawing commands. (It cannot be denied that there is still considerable room for improvement.)

When writing a new device layer you will need to include the following headers:

#include <libwmf/ipa.h>
#include <libwmf/defs.h>

The former includes the API declarations as well as the IPA declarations, while the latter defines metafile constants.

• wmfRGB

  typedef struct _wmfRGB wmfRGB;
  
  struct _wmfRGB
  {	unsigned char r;
  	unsigned char g;
  	unsigned char b;
  };
  

  wmfRGB describes a color, with r = g = b = 255 corresponding to white and r = g = b = 0 corresponding to black.

• wmfBMP

  typedef struct _wmfBMP wmfBMP;
  
  struct _wmfBMP
  {	U16 width;
  	U16 height;
  
  	void* data;
  };
  

  Container for a bitmap, of dimensions width and height. If non-zero, data is a pointer to an internal representation of the bitmap. The interpreter does not reference data and will not attempt to draw a bitmap if data is zero; however, a bitmap brush pattern may be set even though data is zero. (data=0 indicates either that the device layer has no support for bitmaps or that the bitmap is corrupt or unreadable.)

• wmfBrush

  typedef struct _wmfBrush wmfBrush;
  
  struct _wmfBrush
  {	U16 lbStyle;
  	U16 lbHatch;
  
  	wmfRGB lbColor;
  	wmfBMP bmp;
  };
  

  wmfBrush is one element of the current drawing context. lbStyle is one of the following:

  /* Brush Styles */
  #define BS_SOLID            0
  #define BS_NULL             1
  #define BS_HOLLOW     BS_NULL
  #define BS_HATCHED          2
  #define BS_PATTERN          3
  #define BS_INDEXED          4
  #define BS_DIBPATTERN       5
  #define BS_DIBPATTERNPT     6
  #define BS_PATTERN8X8       7
  #define BS_DIBPATTERN8X8    8
  

  where BS_NULL indicates that no brush is set. If lbStyle=BS_HATCHED then the brush has the pattern, specified by lbHatch which is one of:

  /* Hatch Styles */
  #define HS_HORIZONTAL       0       /* ----- */
  #define HS_VERTICAL         1       /* ||||| */
  #define HS_FDIAGONAL        2       /* \\\\\ */
  #define HS_BDIAGONAL        3       /* ///// */
  #define HS_CROSS            4       /* +++++ */
  #define HS_DIAGCROSS        5       /* xxxxx */
  

  If lbStyle=BS_HATCHED or lbStyle=BS_SOLID then the foreground color of the brush is lbColor. Otherwise, if the brush is a bitmap, ensure that bmp.data is non-zero.

  The following macros should be used to retrieve the above info.:

  #include 
  
  /* WMF_BRUSH_STYLE(wmfBrush* B) -> (U16) brush style
   * WMF_BRUSH_HATCH(wmfBrush* B) -> (U16) brush hatch style
   * 
   * WMF_BRUSH_COLOR(wmfBrush* B) -> (wmfRGB*) brush color
   * 
   * WMF_BRUSH_BITMAP(wmfBrush* B) -> (wmfBMP*) brush bitmap
   */
  #define WMF_BRUSH_STYLE(B)  ((B)->lbStyle)
  #define WMF_BRUSH_HATCH(B)  ((B)->lbHatch)
  
  #define WMF_BRUSH_COLOR(B)  (&((B)->lbColor))
  
  #define WMF_BRUSH_BITMAP(B) (&((B)->bmp))
  

• wmfPen

  typedef struct _wmfPen wmfPen;
  
  struct _wmfPen
  {	U16 lopnStyle;
  
  	double width;
  	double height;
  
  	wmfRGB lopnColor;
  };
  

  wmfPen is one element of the current drawing context. The nib has dimensions width and height and color lopnColor. lopnStyle contains style information on the line itself, on the ends, on the joins, and on the type:

  #define PS_STYLE_MASK       0x0000000F
  #define PS_ENDCAP_MASK      0x00000F00
  #define PS_JOIN_MASK        0x0000F000
  #define PS_TYPE_MASK        0x000F0000
  

  lopnStyle & PS_STYLE_MASK is one of:

  #define PS_SOLID            0
  #define PS_DASH             1       /* -------  */
  #define PS_DOT              2       /* .......  */
  #define PS_DASHDOT          3       /* _._._._  */
  #define PS_DASHDOTDOT       4       /* _.._.._  */
  #define PS_NULL             5
  #define PS_INSIDEFRAME      6
  #define PS_USERSTYLE        7
  #define PS_ALTERNATE        8
  

  where PS_NULL indicates that no pen has been set. lopnStyle & PS_ENDCAP_MASK is one of:

  #define PS_ENDCAP_ROUND     0x00000000
  #define PS_ENDCAP_SQUARE    0x00000100
  #define PS_ENDCAP_FLAT      0x00000200
  

  and lopnStyle & PS_JOIN_MASK is one of:

  #define PS_JOIN_ROUND       0x00000000
  #define PS_JOIN_BEVEL       0x00001000
  #define PS_JOIN_MITER       0x00002000
  

  Finally, lopnStyle & PS_TYPE_MASK is one of:

  #define PS_COSMETIC         0x00000000
  #define PS_GEOMETRIC        0x00010000
  

  The following macros should be used to retrieve the above info.:

  #include 
  
  /* WMF_PEN_STYLE(wmfPen* P)  -> (U16) pen style
   * WMF_PEN_ENDCAP(wmfPen* P) -> (U16) endcap style
   * WMF_PEN_JOIN(wmfPen* P)   -> (U16) join style
   * WMF_PEN_TYPE(wmfPen* P)   -> (U16) `type' of pen (??)
   * 
   * WMF_PEN_WIDTH(wmfPen* P)  -> (double) pen `width'  (thickness w.r.t. x-axis)
   * WMF_PEN_HEIGHT(wmfPen* P) -> (double) pen `height' (thickness w.r.t. y-axis)
   * 
   * WMF_PEN_COLOR(wmfPen* P) -> (wmfRGB*) pen color
   */
  #define WMF_PEN_STYLE(P)  ((P)->lopnStyle & PS_STYLE_MASK)
  #define WMF_PEN_ENDCAP(P) ((P)->lopnStyle & PS_ENDCAP_MASK)
  #define WMF_PEN_JOIN(P)   ((P)->lopnStyle & PS_JOIN_MASK)
  #define WMF_PEN_TYPE(P)   ((P)->lopnStyle & PS_TYPE_MASK)
  
  #define WMF_PEN_WIDTH(P)  ((P)->width)
  #define WMF_PEN_HEIGHT(P) ((P)->height)
  
  #define WMF_PEN_COLOR(P)  (&((P)->lopnColor))
  

• wmfFont

  typedef struct _wmfFont wmfFont;
  
  struct _wmfFont
  {	U16 lfHeight;
  	U16 lfWidth;
  
  	S16 lfEscapement;
  	S16 lfOrientation;
  
  	U16 lfWeight;
  
  	U8 lfItalic;
  	U8 lfUnderline;
  	U8 lfStrikeOut;
  	U8 lfCharSet;
  	U8 lfOutPrecision;
  	U8 lfClipPrecision;
  	U8 lfQuality;
  	U8 lfPitchAndFamily;
  
  	char* lfFaceName;
  
  	char* ps_name;
  
  	FT_Face ft_face;
  };
  

  wmfFont is one element of the current drawing context. Of all of this, the most important elements are ps_name (the postscript font name) and ft_face, the freetype (2) font face for which bold and italics have already been determined.

  The following macros should be used to retrieve the above info.:

  #include 
  
  /* WMF_TEXT_ANGLE(wmfFont* F) -> (double) text angle in radians
   * 
   * WMF_TEXT_UNDERLINE(wmfFont* F) -> (U8) ?? whether to underline (?? how thick)
   * WMF_TEXT_STRIKEOUT(wmfFont* F) -> (U8) ?? whether to strikeout (?? how thick)
   * 
   * WMF_FONT_NAME(wmfFont* F)   -> (char*) font name supplied by metafile
   * WMF_FONT_PSNAME(wmfFont* F) -> (char*) font name to use in postscript output
   * WMF_FONT_FTFACE(wmfFont* F) -> (FT_Face) freetype(2) font face
   */
  #define WMF_TEXT_ANGLE(F)     ((((double) (F)->lfEscapement) / 10) * M_PI / 180)
  
  #define WMF_TEXT_UNDERLINE(F) ((F)->lfUnderline)
  #define WMF_TEXT_STRIKEOUT(F) ((F)->lfStrikeOut)
  
  #define WMF_FONT_NAME(F)   ((F)->lfFaceName)
  #define WMF_FONT_PSNAME(F) ((F)->ps_name)
  #define WMF_FONT_FTFACE(F) ((F)->ft_face)
  

• wmfDC

  typedef struct _wmfDC wmfDC;
  
  struct _wmfDC
  {	void* userdata;
  
  	wmfBrush* brush;
  	wmfPen* pen;
  	wmfFont* font;
  
  	int key;     /* Is this used ?? */
  
  	wmfDC* next; /* Is this used ?? */
  
  	wmfRGB textcolor;
  	wmfRGB bgcolor;
  
  	U16 textalign;
  	U16 bgmode;
  	U16 polyfillmode;
  	U16 charextra;
  	U16 breakextra;
  
  	U16 ROPmode;
  
  	struct
  	{	S32 Ox;
  		S32 Oy;
  		S32 width;
  		S32 height;
  	} Window;
  
  	double pixel_width; /* Display pixel dimensions (inches) */
  	double pixel_height;
  
  	U16 map_mode;
  
  	void* clip;
  };
  

  Still very much a work in progress, especially with regard to the drawing context wmfDC; there is much in this structure that is (or should be) irrelevant to the IPA.

  See wmfBrush, wmfPen and wmfFont. textcolor is the color to draw text, bgcolor is the background color (generally, as well as with text) unless bgmode=TRANSPARENT, in which case there is no background. bgmode is one of:

  #define TRANSPARENT         1
  #define OPAQUE              2
  #define BKMODE_LAST         2
  

  The following macros should be used to retrieve the above info.:

  #include 
  
  /* WMF_DC_BRUSH(wmfDC* C) -> (wmfBrush*) current brush
   * WMF_DC_PEN(wmfDC* C)   -> (wmfPen*)   current pen
   * WMF_DC_FONT(wmfDC* C)  -> (wmfFont*)  current font
   * 
   * WMF_DC_TEXTCOLOR(wmfDC* C)  -> (wmfRGB*) text color
   * WMF_DC_BACKGROUND(wmfDC* C) -> (wmfRGB*) background color
   * 
   * WMF_DC_OPAQUE(wmfDC* C) -> (U16) whether to fill opaque (non-zero if true)
   * 
   * WMF_DC_POLYFILL(wmfDC* C) -> (U16) how to fill polygons
   * 
   * WMF_DC_ROP(wmfDC* C) -> (U16) ROP mode
   */
  #define WMF_DC_BRUSH(C)      ((C)->brush)
  #define WMF_DC_PEN(C)        ((C)->pen)
  #define WMF_DC_FONT(C)       ((C)->font)
  
  #define WMF_DC_TEXTCOLOR(C)  (&((C)->textcolor))
  #define WMF_DC_BACKGROUND(C) (&((C)->bgcolor))
  
  #define WMF_DC_OPAQUE(C)     ((C)->bgmode - 1)
  
  #define WMF_DC_POLYFILL(C)   ((C)->polyfillmode)
  
  #define WMF_DC_ROP(C)        ((C)->ROPmode)
  

• wmfFlood_t

  typedef struct _wmfFlood_t wmfFlood_t;
  
  struct _wmfFlood_t
  {	wmfDC* dc;
  
  	wmfD_Coord pt;
  	wmfRGB color;
  
  	U16 type;
  
  	double pixel_width;
  	double pixel_height;
  };
  

  Flood-fill region with color color, starting at point pt. Since this is almost certainly not a vector operation, the pixel width and height are given (and are probably best ignored...). type is one of:

  #define  FLOODFILLBORDER    0
  #define  FLOODFILLSURFACE   1
  

• wmfDrawPixel_t

  typedef struct _wmfDrawPixel_t wmfDrawPixel_t;
  
  struct _wmfDrawPixel_t
  {	wmfDC* dc;
  
  	wmfD_Coord pt;
  	wmfRGB color;
  
  	double pixel_width;
  	double pixel_height;
  };
  

  Set pixel at point pt to color color. The pixel width and height are given.

• wmfDrawArc_t

  typedef struct _wmfDrawArc_t wmfDrawArc_t;
  
  struct _wmfDrawArc_t
  {	wmfDC* dc;
  
  	wmfD_Coord TL;
  	wmfD_Coord BR;
  
  	wmfD_Coord start; /* draw_ellipse: (ignored) */
  	wmfD_Coord end;
  };
  

  Draw a complete or partial ellipse. TL and BR are the coordinates of the top left and bottom right of the ellipse's bounding box respectively. If incomplete, then start and end give the start and end coordinates of the arc.

• wmfDrawLine_t

  typedef struct _wmfDrawLine_t wmfDrawLine_t;
  
  struct _wmfDrawLine_t
  {	wmfDC* dc;
  
  	wmfD_Coord from;
  	wmfD_Coord to;
  };
  

  Draw line from point from to point to.

• wmfPolyLine_t

  typedef struct _wmfPolyLine_t wmfPolyLine_t;
  
  struct _wmfPolyLine_t
  {	wmfDC* dc;
  
  	wmfD_Coord* pt;
  
  	U16 count;
  };
  

  An array (of length count) of points pt[]. This may be used to describe polygons as well as line sequences.

• wmfDrawRectangle_t

  typedef struct _wmfDrawRectangle_t wmfDrawRectangle_t;
  
  struct _wmfDrawRectangle_t
  {	wmfDC* dc;
  
  	wmfD_Coord TL;
  	wmfD_Coord BR;
  
  	float width; /* draw_rectangle: axes of corner ellipses; zero if un-rounded */
  	float height;
  };
  

  A rectangle, possibly with rounded corners - in which case width and height give the elliptic axes of the rectangle's corners.

• wmfPolyRectangle_t

  typedef struct _wmfPolyRectangle_t wmfPolyRectangle_t;
  
  struct _wmfPolyRectangle_t
  {	wmfDC* dc;
  
  	wmfD_Coord* TL; /* region_frame & region_paint: TL[count],BR[count] give the */
  	wmfD_Coord* BR; /* final `extents'... */
  
  	unsigned int count;
  
  	float width;  /* region_frame: border thickness; zero otherwise */
  	float height;
  };
  

  Used by region and clip calls, wmfPolyRectangle_t is used to describe multiple rectangles, whose top left and bottom right corners are given by the TL and BR arrays respectively. These arrays are of length count in the case of clip calls, and of length count + 1 in the case of the region calls, the extra element containing the overall bounding box (the region extents). In the case of region_frame, width and height give the thickness of the frame.

• wmfBMP_Read_t

  typedef struct _wmfBMP_Read_t wmfBMP_Read_t;
  
  struct _wmfBMP_Read_t          /* Two means available for accessing BMP image:        */
  {	long offset;           /* (1) position in source file of start of BMP;        *
                                  * use API->bbuf.seek to set pos(ition), etc.          */
  	long length;           /* (2) buffer of length length containing image of BMP */
  	unsigned char* buffer;
  
  	U16 width;  /* WMF player may preset these values; zero otherwise. */
  	U16 height; /* Use caution - may be buggy... ?? [TODO]             */
  
  	wmfBMP bmp;
  };
  

  There are two ways to read a bitmap presented by libwmf: the first is to read it directly from the input stream using the internal stream functions:

  /* Macro-wrappers for stream functions:
   * (int)  WMF_READ ((wmfAPI*) API)                 - returns unsigned char cast to int, or EOF
   * (int)  WMF_SEEK ((wmfAPI*) API,(long) position) - returns (-1) on error, else 0
   * (long) WMF_TELL ((wmfAPI*) API)                 - returns (-1) on error, else current position
   */
  

  where the bitmap starts at offset offset; the second (which is preferred) is to use the buffer buffer of length length.

  To complicate matters, the bitmap's data may be truncated so that the bitmap's header is incorrect - width and height give the real dimensions of the bitmap.

  The bitmap's width and height should be entered into bmp (see wmfBMP above) as well as a pointer to the bitmap data (which can be in any format you choose; the library does not need to know).

• wmfBMP_Draw_t

  typedef struct _wmfBMP_Draw_t wmfBMP_Draw_t;
  
  struct _wmfBMP_Draw_t
  {	wmfDC* dc;
  
  	wmfD_Coord pt;
  	wmfBMP bmp;
  
  	U32 type;
  
  	struct
  	{	U16 x;
  		U16 y;
  		U16 w;
  		U16 h;
  	} crop;
  
  	double pixel_width;
  	double pixel_height;
  };
  

  In contrast to earlier versions, libwmf no longer makes any attempt to crop or scale the bitmap. Instead the crop data are presented to the device layer to use as it sees fit, and the pixel width and height as well. The bitmap referenced by bmp (see wmfBMP above) is to be drawn at point pt.

  TODO: info on type

• wmfROP_Draw_t

  typedef struct _wmfROP_Draw_t wmfROP_Draw_t;
  
  struct _wmfROP_Draw_t
  {	wmfDC* dc;
  
  	wmfD_Coord TL;
  	wmfD_Coord BR;
  
  	U32 ROP;
  
  	double pixel_width;
  	double pixel_height;
  };
  

  TODO:

• wmfDrawText_t

  typedef struct _wmfDrawText_t wmfDrawText_t;
  
  struct _wmfDrawText_t
  {	wmfDC* dc;
  
  	wmfD_Coord pt;
  
  	wmfD_Coord TL; /* Clip zone */
  	wmfD_Coord BR;
  
  	struct /* An estimated surround zone */
  	{	wmfD_Coord TL;
  		wmfD_Coord TR;
  		wmfD_Coord BL;
  		wmfD_Coord BR;
  	} bbox;
  
  	char* str;
  
  	U16 flags;
  
  	double font_height;
  	double font_ratio;  /* width to height ratio */
  };
  

  Fonts and text are triiicky! Fortunately libwmf tries to do most of the work. As such text justification is taken care of by the interpreter, and fonts (bold, italic, etc.) are selected elsewhere. The emphasis with wmfDrawText_t is therefore the rendering of text.

  The text can be assumed to be left-justified, starting at point pt. TL and BR are the corners of a clip rectangle. bbox gives four corners of rectangle - an estimate of the background zone. str is the text to draw; font_height is the height of the font and font_ratio is how much to stretch the font width-wise. The values for flags are:

  #define ETO_OPAQUE          0x0002
  #define ETO_CLIPPED         0x0004
  #define ETO_GLYPH_INDEX     0x0010
  #define ETO_RTLREADING      0x0080
  

• wmfUserData_t

  typedef struct _wmfUserData_t wmfUserData_t;
  
  struct _wmfUserData_t	/* TODO: Need to be careful with usage here; not all these are set by the player! */
  {	wmfDC* dc;          /* dc is guaranteed */
  
  	void* data;         /* data also, except for init */
  };
  

  Redundant; may be removed at some point...

• wmfCharDrawer

  typedef void (*wmfCharDrawer) (wmfAPI*,wmfDrawText_t*);
  

Let us assume that you are writing a device layer called mydev, then the first requirement is an initialization function:

#include <libwmf/ipa.h>
#include <libwmf/defs.h>
#include <libwmf/mydev.h>

void wmf_mydev_function (wmfAPI* API)
{	wmfFunctionReference* FR = (wmfFunctionReference*) API->function_reference;

	/* */

typedef struct _wmfFunctionReference wmfFunctionReference;

struct _wmfFunctionReference
{	void (*device_open) (wmfAPI*);
	void (*device_close) (wmfAPI*);
	void (*device_begin) (wmfAPI*);
	void (*device_end) (wmfAPI*);

	void (*flood_interior) (wmfAPI*,wmfFlood_t*);
	void (*flood_exterior) (wmfAPI*,wmfFlood_t*);

	void (*draw_pixel) (wmfAPI*,wmfDrawPixel_t*);
	void (*draw_pie) (wmfAPI*,wmfDrawArc_t*);
	void (*draw_chord) (wmfAPI*,wmfDrawArc_t*);
	void (*draw_arc) (wmfAPI*,wmfDrawArc_t*);
	void (*draw_ellipse) (wmfAPI*,wmfDrawArc_t*);
	void (*draw_line) (wmfAPI*,wmfDrawLine_t*);
	void (*poly_line) (wmfAPI*,wmfPolyLine_t*);
	void (*draw_polygon) (wmfAPI*,wmfPolyLine_t*);
	void (*draw_rectangle) (wmfAPI*,wmfDrawRectangle_t*);

	void (*rop_draw) (wmfAPI*,wmfROP_Draw_t*);
	void (*bmp_draw) (wmfAPI*,wmfBMP_Draw_t*);
	void (*bmp_read) (wmfAPI*,wmfBMP_Read_t*);
	void (*bmp_free) (wmfAPI*,wmfBMP*);

	void (*draw_text) (wmfAPI*,wmfDrawText_t*);

	void (*udata_init) (wmfAPI*,wmfUserData_t*);
	void (*udata_copy) (wmfAPI*,wmfUserData_t*);
	void (*udata_set) (wmfAPI*,wmfUserData_t*);
	void (*udata_free) (wmfAPI*,wmfUserData_t*);

	void (*region_frame) (wmfAPI*,wmfPolyRectangle_t*);
	void (*region_paint) (wmfAPI*,wmfPolyRectangle_t*);
	void (*region_clip) (wmfAPI*,wmfPolyRectangle_t*);
};

The initialization function has two purposes, the first being to establish the links that create the IPA by pointing the function reference variables to your own drawing functions:

#include <libwmf/ipa.h>
#include <libwmf/defs.h>
#include <libwmf/mydev.h>

void wmf_mydev_function (wmfAPI* API)
{	wmfFunctionReference* FR = (wmfFunctionReference*) API->function_reference;

	FR->device_open  = wmf_mydev_device_open;
	FR->device_close = wmf_mydev_device_close;
	FR->device_begin = wmf_mydev_device_begin;
	FR->device_end   = wmf_mydev_device_end;
	/* etc. */

	/* */
}

void wmf_mydev_device_open (wmfAPI* API)
{	/* */
}

/* etc. */

The second purpose of the initialization function is to allocate the device's data structure, set the device parameters to default values if necessary, and then to attach the data to the API->device_data hook.

/* */

typedef struct _wmf_mydev_t wmf_mydev_t;

struct _wmf_mydev_t
{	/* */

	unsigned long flags;
}

void wmf_mydev_function (wmfAPI* API)
{	wmfFunctionReference* FR = (wmfFunctionReference*) API->function_reference;

	wmf_mydev_t* ddata = 0;

	FR->device_open  = wmf_mydev_device_open;
	/* etc. */

	API->device_data = wmf_malloc (API,sizeof (wmf_mydev_t));

	if (API->err != wmf_E_None) return; /* insufficient memory? */

	ddata = (wmf_mydev_t*) API->device_data;

	/* */

	ddata->flags = 0;
}

/* */

The IPA functions are called by wmf_play (), the only exception being device_close which is called by wmf_api_destroy () - and then only if device_open has been called by wmf_play ().

device_open is called the first time (and only the first time) wmf_play () is called, and is the very first IPA function to be called, just as device_close will be the very last.

At the beginning of each play cycle (i.e., each call to wmf_play ()) device_begin is called (after device_open if it is the first cycle), and at the end of each cycle device_end is called. The metafile graphics use other IPA functions.

device_open, device_begin, device_end and device_close should be written so that wmf_play () can be called repeatedly.

The names of the functions are not important. The generic names are used below:

• device_open

  void device_open (wmfAPI*);
  

  device_open is the very first IPA function to be called. It is called only once, the first time wmf_play () is called.

• device_close

  void device_close (wmfAPI*);
  

  device_close is the very last IPA function to be called. It is called by wmf_api_destroy (), and only if device_open has been called earlier.

• device_begin

  void device_begin (wmfAPI*);
  

  device_begin is the first IPA function called from wmf_play () (with the exception of device_open the first time wmf_play () is called).

• device_end

  void device_end (wmfAPI*);
  

  device_end is the last IPA function called from wmf_play ().

• flood_interior

  void flood_interior (wmfAPI*,wmfFlood_t*);
  

• flood_exterior

  void flood_exterior (wmfAPI*,wmfFlood_t*);
  

• draw_pixel

  void draw_pixel (wmfAPI*,wmfDrawPixel_t*);
  

• draw_pie

  void draw_pie (wmfAPI*,wmfDrawArc_t*);
  

• draw_chord

  void draw_chord (wmfAPI*,wmfDrawArc_t*);
  

• draw_arc

  void draw_arc (wmfAPI*,wmfDrawArc_t*);
  

• draw_ellipse

  void draw_ellipse (wmfAPI*,wmfDrawArc_t*);
  

• draw_line

  void draw_line (wmfAPI*,wmfDrawLine_t*);
  

• poly_line

  void poly_line (wmfAPI*,wmfPolyLine_t*);
  

• draw_polygon

  void draw_polygon (wmfAPI*,wmfPolyLine_t*);
  

• draw_rectangle

  void draw_rectangle (wmfAPI*,wmfDrawRectangle_t*);
  

• rop_draw

  void rop_draw (wmfAPI*,wmfROP_Draw_t*);
  

  TODO:

• bmp_draw

  void bmp_draw (wmfAPI*,wmfBMP_Draw_t*);
  

  Note: Unless you're feeling masochistic and want to write, or re-write, your own suite of functions for the reading, writing and general manipulation of bitmaps, you should defer this to libwmf's built-in support which is adapted from ImageMagick's excellent BMP coder.

  See section on bitmaps below.

• bmp_read

  void bmp_read (wmfAPI*,wmfBMP_Read_t*);
  

  Note: Unless you're feeling masochistic and want to write, or re-write, your own suite of functions for the reading, writing and general manipulation of bitmaps, you should defer this to libwmf's built-in support which is adapted from ImageMagick's excellent BMP coder.

  void bmp_read (wmfAPI* API,wmfBMP_Read_t* bmp_read)
  {	wmf_ipa_bmp_read (API,bmp_read);
  }
  

• bmp_free

  void bmp_free (wmfAPI*,wmfBMP*);
  

  Note: Unless you're feeling masochistic and want to write, or re-write, your own suite of functions for the reading, writing and general manipulation of bitmaps, you should defer this to libwmf's built-in support which is adapted from ImageMagick's excellent BMP coder.

  void bmp_free (wmfAPI* API,wmfBMP* bmp)
  {	wmf_ipa_bmp_free (API,bmp);
  }
  

• draw_text

  void draw_text (wmfAPI*,wmfDrawText_t*);
  

  If desired, strings can be decomposed into individual chars using wmf_ipa_draw_text (). Best to see source for the various device layers in libwmf.

• udata_init

  void udata_init (wmfAPI*,wmfUserData_t*);
  

  Redundant; may be removed at some point...

• udata_copy

  void udata_copy (wmfAPI*,wmfUserData_t*);
  

  Redundant; may be removed at some point...

• udata_set

  void udata_set (wmfAPI*,wmfUserData_t*);
  

  Redundant; may be removed at some point...

• udata_free

  void udata_free (wmfAPI*,wmfUserData_t*);
  

  Redundant; may be removed at some point...

• region_frame

  void region_frame (wmfAPI*,wmfPolyRectangle_t*);
  

• region_paint

  void region_paint (wmfAPI*,wmfPolyRectangle_t*);
  

• region_clip

  void region_clip (wmfAPI*,wmfPolyRectangle_t*);
  

  If the number of clip rectangles is zero, the current clip region should be unset.

The section applies only if you are working on the libwmf sources.

The build system uses automake and autoconf. If any changes are made to any of the various Makefile.am files, or to configure.in or libwmf.m4, then the build system will need to be updated. Change to the top source directory (containing configure.in and libwmf.m4) and:

# aclocal
# automake
# autoheader
# autoconf
# date > stamp-h.in

When adding a new device layer, include/libwmf/Makefile.am and src/ipa/Makefile.am will need to be modifiled. Source files (src/ipa/new.c) and installing header files (include/libwmf/new.h) do not need to be added to the distribution, but other headers (src/ipa/new.h & src/ipa/new/*.h) will.